In contrast, the nonenzymatic process adds glucose haphazardly to any of several sites along any available peptide chain within a protein molecule.

The brain cells containing these mRNA's can then be isolated and their mRNA's decoded to determine just what their protein products are and how closely the products resemble the true peptide hormones.

Antagonists tend to be small molecules that bind irreversibly to the receptor preventing its normal function, while agonists may be small or large molecules (e.g. peptide or protein hormones).